Packaging machine and associated film gripper

ABSTRACT

A packaging machine for use in packaging a product using rolled wrap film includes a packaging station where film is to be manipulated during a packaging operation, a support for holding rolled film and located to permit film to be drawn into the packaging station and a film grip assembly for gripping at least one edge of film during at least part of a packaging operation. The film grip assembly includes a first jaw element, a second jaw element mounted for movement between a gripping position and a non-gripping position relative to the first jaw element and at least one pneumatic actuator positioned at least partially between the first jaw element and the second jaw element for selectively moving the second jaw element.

TECHNICAL FIELD

The present application relates to machines that can be used for positioning film about a product, and more particularly to a machine employing a gripper assembly including a movable jaw element.

BACKGROUND

Products such as, for example, perishable food products are frequently transported and/or stored with wrap film disposed about a periphery of the product to provide a degree of isolation of the wrapped product from the surroundings. Frequently, an apparatus is employed for automating the film wrapping process. As an example, an apparatus has been proposed having a gripper for gripping and locating a sheet of film. The gripper includes a solenoid that controls opening and closing of the gripper.

SUMMARY

In an aspect, a packaging machine for use in packaging a product using rolled film includes a packaging station where film is to be manipulated during a packaging operation, a support for holding rolled film and located to permit film to be drawn into the packaging station and a film grip assembly for gripping at least one edge of film during at least part of a packaging operation. The film grip assembly includes a first jaw element, a second jaw element mounted for movement between a gripping position and a non-gripping position relative to the first jaw element and at least one pneumatic actuator positioned at least partially between the first jaw element and the second jaw element for selectively moving the second jaw element.

In another aspect, a package wrapping machine for wrapping packages using rolled wrap film includes a wrap station where wrap film is to be wrapped around a product, a support for holding rolled wrap film and located to permit wrap film to be drawn into the wrap station and a film grip assembly for gripping at least one edge of wrap film as it is drawn into the wrap station. The film grip assembly is movable in a film draw direction and includes a first jaw element, a second jaw element mounted for pivotal movement between a gripping position and a non-gripping position relative to the first jaw element, the second jaw element biased into the non-gripping position and at least one pneumatic actuator positioned between the first jaw element and the second jaw element for selectively causing the second jaw element to pivot into the gripping position.

In another aspect, in a package wrapping machine for wrapping packages using rolled wrap film, a method is provided for selectively gripping rolled wrap film using a film gripper that includes a first jaw element and a second jaw element, the second jaw element movable between a gripping position and a non-gripping position relative to the first jaw element. The method includes utilizing a pneumatic actuator positioned between the first jaw element and the second jaw element to selectively control whether the second jaw element is in the gripping position, including controlling delivery of pressurized fluid to the pneumatic actuator.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of a wrapping machine.

FIGS. 2 and 3 are perspective views of an embodiment of a gripper assembly suitable for use in the machine of FIG. 1.

FIG. 4 is a section view of the gripper assembly of FIG. 2 taken along line 4-4 showing a jaw element in a gripping position.

FIG. 5 is a section view of a cylinder of the gripper assembly of FIG. 4.

FIG. 6 is a section view of a piston of the gripper assembly of FIG. 4.

FIG. 7 is a section view of the gripper assembly of FIG. 2 along line 4-4 with the lower jaw element in a non-gripping position.

FIG. 8 is a section view of the gripper assembly of FIG. 2 along line 4-4 with a lower jaw element in a gripping position.

FIGS. 9 is a perspective views of a subassembly embodiment of a wrapping machine including the film gripper.

DETAILED DESCRIPTION

Referring to FIG. 1, a package wrapping machine 100 includes an in-feed portion 102 at which a product 104, e.g., a perishable item such as food can be introduced to the machine 100, a wrap station 106 (see also FIGS. 9 and 10) at which the product 104 can be wrapped, e.g., by a wrap film such as a food contact grade film, and an out-feed portion 108 (FIG. 9) at which the wrapped product can be accessed, e.g., to remove the product 104 from the machine 100. Referring to FIG. 9, as will be discussed in greater detail below, the package wrapping machine 100 includes a gripper assembly 110 having multiple jaw elements 112, 114 and 116 driven by respective actuators 162 (FIG. 2). The jaw elements can be used to grasp film 118 of a continuous roll 120, 122 of film to draw the film 118 into the wrap station 106 and position the film 118 about the product 104.

Referring to FIG. 2, the gripper assembly 110 includes an upper jaw element 124 and three lower jaw elements 112, 114 and 116. The number of lower jaw elements may be increased or decreased depending on the application. Each of the lower jaw elements 112, 114 and 116 are pivotally coupled to the upper jaw element 124 to allow for pivoting of the lower jaw elements 112, 114, 116 relative to the upper jaw element 124. In the illustrated embodiment, as shown, the lower jaw elements 112, 114 and 116 are coupled to the upper jaw element 124 to allow each lower jaw element to be moved independently of the other lower jaw elements. This arrangement can provide greater flexibility, e.g., to accommodate a variety of film sheet widths. The arrangement also permits selective release of certain portions of the film during wrapping. In an alternative embodiment, the lower jaw elements 112, 114 and 116 are coupled together such that the lower jaw elements 112, 114 and 116 may be pivoted in unison (not shown). This arrangement can allow use of only one actuator 162 to actuate more than one of the lower jaw elements.

Referring now to FIGS. 3 and 4, the upper jaw element 124 includes an elongated plate 126 and an array of spaced-apart upper projections 128 extending integrally from a front edge 130 (FIG. 3) of the plate 126. Each projection 128 includes an upper traction member 132 (e.g., formed of plastic or rubber) that can facilitate grasping and releasing of film during use. As shown most clearly by FIG. 2, the traction members 132 have a flat lower surface 134. However, any suitable configuration can be employed such as a traction member including one or more teeth (not shown) extending outwardly from the surface 134 (e.g., which can mate with corresponding teeth 136 extending from the lower gripper elements 112, 114 and 116).

Referring still to FIGS. 3 and 4, extending from a rear edge 138 of the plate 126 are pair of mounting members 140, 142 (FIG. 3). The mounting members 140, 142 each provide a location at which a mounting assembly 144 can be connected to the upper jaw element 124. The mounting assembly 144 in turn provides a connection between the upper jaw element 124 and, for example, slide blocks mounted for movement in the wrapping machine.

The lower jaw elements 112, 114 and 116 are pivotally mounted to the upper jaw element 124 at a respective pivot axis A, B and C. Axes A, B and C are substantially parallel to a lower surface 152 of the upper jaw member 124 and each axis A, B and C also extends along a common line D (FIG. 2). Other configurations are also envisioned such as offset, non aligned axes. Pivotally coupling the upper jaw element 124 and lower jaw elements 112, 114 and 116 are coupling assemblies 154 that include a pivot rod 156 and mounting brackets 158, each mounting bracket 158 having an aperture 160 sized to slidably receive the pivot rod 156.

Referring back to FIG. 2 and also to FIG. 4, the lower jaw elements 112, 114 and 116 include a forward gripping portion 146 located forward of the associated pivot axis and a rear receiving portion 148 located rearward of the associated pivot axis. The forward gripping portion 146 includes an array of spaced-apart lower projections 150 that oppose the upper projections 128 during a gripping operation. Each lower projection 150 includes a traction member 132 (e.g., formed of plastic or rubber) having an array of teeth 136 that can facilitate grasping and releasing of film during use.

As noted above, actuators 162 (e.g., a pneumatic actuator or a hydraulic actuator) drive the lower jaw elements 112, 114 and 116 about their respective pivot axis. Other devices are also contemplated, such as an electric solenoid (e.g., an electric solenoid having horizontal travel and motion translation to vertical motion), for driving the lower jaw elements 112, 114 and 116. Referring particularly to FIG. 4, the actuators 162 are positioned between the upper jaw element 124 and associated lower jaw elements 112, 114, 116 and each actuator 162 includes a cylinder 164 (FIG. 5) and a piston 166 (FIG. 6). Referring to FIGS. 5 and 6, the cylinder 164 has a primary bore 168 of length L that is sized to receive a base 170 of the piston 166 and a secondary bore 172 sized to receive a shaft 174 of the piston 166. The height H of the cylinder may be less than about 1.5 inches in one embodiment, less than about 1.25 inches in another embodiment, or less than about one inch in still another embodiment. Such heights, which are exemplary only, provide a relatively low profile for the gripper assembly that will not occupy a large amount of space in the wrapping machine. As will be described below, the secondary bore 172 allows a rounded nose portion 176 of the piston shaft 174 to extend beyond an end 178 of the cylinder 164 to actuate the associated lower jaw element from an initial, non-gripping position toward a gripping position. Other nose configurations are also contemplated, such as a squared end, pointed end, angled side surfaces or any combination of rounded, pointed and/or angled surfaces.

Referring again to FIG. 4, the cylinder 164 extends outwardly from and is rigidly connected to the lower surface 152 of the upper jaw element 124 within a recess 180 such that surface 152 forms a rear portion of the actuator 162 by sealing the end of the cylinder. As shown, cylinder 164 is connected to the upper jaw element 124 by one or more fasteners 165. Any other suitable attachment method can be used to rigidly connect the upper jaw element 124 and cylinder 164 including, for example, welding. Inner surface 182 of the cylinder 164, lower surface 152 of the lower jaw element 124 and a rear surface 184 of the base 170 of piston 166 form a chamber 186 that can be pressurized (e.g., by pressurized fluid such as air) to translate the piston 166 within the cylinder 164. The chamber 186 is in communication with a device (e.g., a compressor, pressurized vessel, etc.) suitable for pressurizing chamber 186 (e.g., with a fluid, such as air) via a passageway 188 extending from the rear edge 138 and through the upper jaw member 124 (see also FIG. 3). A connector 190 communicates with the passageway 188 and is configured to receive pneumatic tubing for supply and withdrawal of the pressurized fluid from the chamber 186. By forming the rear portion of the actuator 162 using the lower surface 152 of the upper jaw element 124, volume occupied by the gripping assembly 110 within the machine 100 can be minimized. To inhibit unintended pressure loss within the chamber 186 during use, an o-ring 192 having a triangular cross-section is disposed within annular recess 194 and between the inner surface 182 of the cylinder 164 and the piston 166 (FIG. 6). Other types of seals can be used such as o-rings having a round or square cross-section, or a flexible membrane having one end that is fixed and one end that moves with the piston.

As assembled, the primary bore 168 and secondary bore 172 of the cylinder 164 each have a central axis that extends along a line substantially perpendicular to surface 152 forming an imaginary vertical actuation axis E (see also FIGS. 7 and 8) along which shaft 174 can travel during use and that is spaced laterally from the associated pivot axis. This vertical arrangement along with the orientation of the associated lower jaw element relative to the shaft 174 can allow for the use of a relatively short stroke (e.g., in one embodiment at most about one inch while having a bore size large enough to provide a desirable clamping force (e.g., in one embodiment at least about 10 lbs., such as at least about 13 lbs.) with the gripping assembly 110 in a gripping position.

In some embodiments, nose portion 176 of the shaft 174 may be attached (e.g., by welding, adhesives, etc.) to the associated lower jaw element at the receiving portion 148 providing a push-pull arrangement where the shaft 174 can apply both a grasping force and a releasing force to the lower jaw member. In other embodiments, nose portion 176 of the shaft 174 merely contacts, but is not attached to the lower jaw element at the receiving portion 148 providing a push arrangement where the shaft 174 can apply a grasping force to the lower jaw member. In either case, it may be desirable to apply a biasing force at the gripping portion 146, spaced from the associated pivot axis to bias the lower jaw element toward its non-gripping position. This can be accomplished by a spring 196 (shown by dotted lines) and/or counterweight, as examples. In cases where a biasing force is applied, the actuator 162 can apply a grasping force sufficient to overcome the biasing force and also sufficient to allow the associated jaw elements to sufficiently grip the sheet film when the jaw elements are in the gripping position.

Each actuator 162 can be actuated independently of the other actuators 162 to move the associated lower jaw element independently of the other lower jaw elements. Also, all of the actuators 162 or any combination of actuators 162 can be actuated simultaneously to move associated lower jaw members in unison. To exemplify lower jaw element movement, referring to FIGS. 7 and 8, lower jaw element 114 is shown in a non-gripping and gripping position, respectively. Referring to FIG. 7, lower jaw element 114 is shown in its rest position, with the gripping portion 146 spaced vertically from the upper jaw element 124. The piston 166 of the actuator 162 is biased adjacent lower surface 152. In this position, an edge of wrap film (not shown) can be inserted between the upper jaw element 124 and lower jaw element 114. Referring now to FIG. 8, lower jaw element 114 is shown in the gripping position with traction members 132 of upper jaw element 124 and lower jaw element 114 in contact. The piston 166 of the actuator 162 is translated along axis E in the direction of arrow 198, applying a grasping force at the receiving portion 148 and rotating the lower jaw element 114 about axis B (e.g., to grip a sheet of wrap film) in the direction of arrow 200.

Referring now to FIG. 9, subassembly 210 includes the gripper assembly 110 and a pair of rolls 120, 122 of continuous film 118. The rolls 120, 122 of film 118 are supported by support structure 212 positioned to allow the film 118 to be drawn into the wrapping station 106. During use, gripper assembly 110 is manipulated to first move in the direction of arrow 220 to a position to grasp the end of the film. The gripper assembly then moves back in the direction of arrow 222 to draw the film off the roll and into the wrap station 106, where a package is moved upward into the film and then wrapping takes place. By way of example, automated wrapping is further described in U.S. Pat. No. 6,658,820, the details of which are incorporated herein by reference. The gripper assembly 110 is shown located at an intermediate position in the wrap station in FIG. 9.

A number of detailed embodiments have been described. Nevertheless, it will be understood that various modifications may be made. For example, it is recognized that described film support systems would also have use in lidding-type packaging machines where the film is drawn out over a container and then sealed to the top of the container at a lidding station. Accordingly, other embodiments are within the scope of the following claims. 

1. A packaging machine for use in packaging a product using rolled wrap film, the machine comprising: a packaging station where film is to be manipulated during a packaging operation; a support for holding rolled film, the support located to permit film to be drawn into the packaging station; a film grip assembly for gripping at least one edge of film during at least part of a packaging operation, the film grip assembly including: a first jaw element; a second jaw element mounted for movement between a gripping position and a non-gripping position relative to the first jaw element; and at least one pneumatic actuator positioned at least partially between the first jaw element and the second jaw element for selectively moving the second jaw element.
 2. The machine of claim 1 wherein the pneumatic actuator comprises a cylinder with an axial length of less than about 1.5 inches.
 3. The machine of claim 2 wherein the cylinder is rigidly connected to the first jaw element, and a piston is movably positioned within the cylinder.
 4. The machine of claim 3 wherein the axial length of the cylinder is less than about 1.0 inch.
 5. The machine of claim 3 wherein the first jaw element includes a recessed surface portion receiving an end of the cylinder.
 6. The machine of claim 2 wherein an entirety of the cylinder is positioned between the first jaw element and the second jaw element.
 7. The machine of claim 1 wherein the film grip assembly further includes: a third jaw element and a fourth jaw element positioned at respective sides of the second jaw element, both the third jaw element and the fourth jaw element mounted for movement between respective gripping and non-gripping positions relative to the first jaw element; and at least one pneumatic actuator positioned between the first jaw element and the third jaw element for selectively moving the third jaw element; at least one pneumatic actuator positioned between the first jaw element and the fourth jaw element for selectively moving the fourth jaw element; and the pneumatic actuator between the first jaw element and the second jaw element is controllable separately from both the pneumatic actuator between the first jaw element and the third jaw element and the pneumatic actuator between the first jaw element and the fourth jaw element.
 8. The machine of claim 1 wherein the second jaw element is mounted for pivotal movement between the gripping and non-gripping position, the pneumatic actuator contacts the second jaw element to one side of its pivot axis.
 9. The machine of claim 1 wherein the second jaw element is biased into the non-gripping position, and the pneumatic actuator is operable in a push arrangement with the second jaw element and works against the bias when actuated.
 10. The machine of claim 1 wherein the pneumatic actuator is operable in a push-pull arrangement with the second jaw element.
 11. A package wrapping machine for wrapping packages using rolled wrap film, the machine comprising: a wrap station where wrap film is to be wrapped around a product; a support for holding rolled wrap film, the support located to permit wrap film to be drawn into the wrap station; a film grip assembly for gripping at least one edge of wrap film as it is drawn into the wrap station, the film grip assembly movable in a film draw direction and including: a first jaw element; a second jaw element mounted for pivotal movement between a gripping position and a non-gripping position relative to the first jaw element, the second jaw element biased into the non-gripping position; and at least one pneumatic actuator positioned between the first jaw element and the second jaw element for selectively causing the second jaw element to pivot into the gripping position.
 12. The machine of claim 11 wherein one of the first jaw element and the second jaw element is an upper jaw element, the other of the first jaw element and the second jaw element is a lower jaw element, and the pneumatic actuator has an actuation axis that is substantially vertical.
 13. The machine of claim 11 wherein the pneumatic actuator comprises a cylinder arranged between the first jaw element and the second jaw element, a piston within the cylinder and movable along an actuation axis of the actuator, a sealing arrangement between the piston and the cylinder, wherein a high pressure side of the cylinder is positioned against a portion of the first jaw element.
 14. The machine of claim 13 wherein the piston includes a nose portion that extends through an opening in an actuation side of the cylinder for contacting the second jaw element.
 15. The machine of claim 13 wherein the portion of the first jaw element is a recessed portion that receives an end of the cylinder.
 16. The machine of claim 13 wherein the sealing arrangement comprises at least one o-ring disposed between the piston and the cylinder.
 17. The machine of claim 16 wherein the o-ring has a triangular cross-section, with one corner in contact with an inner surface of the cylinder.
 18. The machine of claim 13 wherein the sealing arrangement comprises a flexible membrane.
 19. The machine of claim 13 wherein the cylinder has a length of less than about 1.0 inch.
 20. The machine of claim 13 wherein the portion of the first jaw element includes an opening therein for receiving pressurized air to cause the piston to move away from the first jaw element.
 21. The machine of claim 11 wherein the pneumatic actuator comprises a cylinder with an axial length of less than about 1.5 inches.
 22. The machine of claim 21 wherein an entirety of the cylinder is positioned between the first jaw element and the second jaw element and the cylinder is rigidly connected to the first jaw element, a piston is movably positioned within the cylinder.
 23. The machine of claim 11 wherein a mount bracket is located between the first jaw element and the second jaw element, a pivot rod is supported by the mount bracket and defines a pivot axis of the second jaw element.
 24. In a package wrapping machine for wrapping packages using rolled wrap film, a method for selectively gripping rolled wrap film using a film gripper including a first jaw element and a second jaw element, the second jaw element movable between a gripping position and a non-gripping position relative to the first jaw element, the method comprising: utilizing a pneumatic actuator positioned between the first jaw element and the second jaw element to selectively control whether the second jaw element is in the gripping position, including controlling delivery of pressurized fluid to the pneumatic actuator.
 25. The method of claim 24 wherein the second jaw element is biased into the non-gripping position and the pneumatic actuator works against the bias.
 26. The method of claim 24 wherein the second jaw element is mounted for a pivotal movement and the pneumatic actuator is positioned to one side of a pivot axis of the second jaw element to effect pivoting of the second jaw element. 